I want to execute this comand in bash scripting.
Code:
#!/bin/bash
line=39;
d=d; ## For delete line
`echo "sed '$line$d' /etc/passwd"`;
But when I execute, I got this error:
sed: -e expresion #1, character 1: unknow command <<'>>
I tried with echo "sed \'$line$d\' /etc/passwd";
But same problem...
You need to insure when calling your variables that you do not prevent expansion by single-quoting them. Now it is OK to use single-quotes within double-quotes, but be mindful. Also, though not required, when putting two variables back-to-back, it is better to use braces to insure against ambiguity. That said, your sed command from a script works fine as:
sed -e "${line}${d}" /etc/passwd
Which will output /etc/passwd to stdout minus line $line. To edit /etc/passwd in place, use sed -i
d should be expanded, he wants to remove using sed I believe. Right now there isn't even a sed command... The problem, it seems to me, was that he was trying to end the variable with a dollar instead of encapsulating it with curly braces.
pastebin immediately before the call it does d=d
To delete line 39 simply do:
#!/bin/bash
line=39;
sed -i "${line}d" /etc/passwd
Sed will take the second argument as input file and the first as a command. The extra flag -i will allow you to redirect the output immediately to the input file. Note that this is not the same as sed 'command' file > file as this will result in an empty file.
I also advise executing man sed in your shell.
line 39 from where? output to stdout? or in /etc/passwd?/etc/passwdis the input file, check his code in the pastebin.foo /etc/password only operates on cat /etc/passwd. You must include -i for edit in place.#!/bin/bash
# delete line 39 by editing inline via sed;
sed -i '39d' /etc/passwd
Keep it simple and add the comment if you want remember the sed action
